Regenerative heating apparatus



Oct. 13, 1953 E. T. LINDEROTH 2,655,205,

' REGENERATIVE HEATING APPARATUS Filed Jan. 17, 1950 2 Sheets-Sheet i wm M MM 2 Sheets-Sheet 2 Filed Jan. 17, 1950 0 0'0 0 0 O 0 :9. .l a- 70 0000000000 000 000000000 0 0 00 oo o o o o o o 0 0 o o o o Patented Oct. 13, 1953 ErikfTorvalds' Linderoth; Stockholm,

Sweden"- A'ppli'cati'on January 17, 1950; Serial No. 139,016

9 Claims;

The present invention relates'to a heating ap paratus provided with a regenerator, saidheat ing apparatus being suitable for use with a boiler" preferably intended for steam or hot waterproduction.

The invention comprises a combustion device:

in which intermittent combustion takes place,v and in which the combustion chamber alternately breathes inwardly and outwardly'throu'gh a re"- generator or other heatexchanging' means, without the use of any valves; Burnt gases pass outwardl'y' and combustion. airi'is' drawn. inwardly through the regenerator alternately, a transfer. of heat" from the burnt gases to the: combustion air beingeflfected byheat from theburnt gases which is storedin' the regenerator and: subsequently imparted to theinco'min'g combustion air by reason of the temperature difference between the in comingand outgoing gaseous fluids. In regen-- erative'heat transmission of this-character, it is possible togivethe heat transmitting surface an extremelyeffective shape with respect -to its heat storage and transmitting capacity. he previous disadvantage: has been that saidsurface should bemovable' or be provided with 'complica-tedi luic-- in'g: means. foirmaking' possible the alternate flow of air and hue gas.

A combustion. device breathing through the regenerator in the manner suggested above involvesa great simplification.

A: necessary condition for proper operation" ofi acom'busti'on: device-of this character is'that the volume of: theregenerator and that ofits gas passages shallbevery small; so-thatthe-volumesofburnt gases; and combustion air which fail t pass: completely through: the regenerato'r will: be minimized. Since the volumes of these gaseous fluids which' pulsate" in* and out through" the re-' generator is but a small fraction of the volume of.

the combustion chamber, calculation will indicatethat the" maximum: volume for the heat transfer passages of the regenerator-is'fi offthe volume of the combustion chamber and pref-- erablylessthan 1- or:2 of thercombu'stion chame ber volume;

Moreover; arrangements shouldbe made 'to prevent too great a mixture between the fresh: air' drawn: iniandfremainingcombustion pro ducts: According to the'invention' this is efiected'bytheibreathing: aperture being arrangedpart of: the combustion that the fresh: air" flow-s1 locityin such a direction lation in" the combustion" chamber: in" such I a way that the-thermo-circuchamber is facil'itated;

on alternatively, guide members' mayf beprov-ided: 55-

in" with: at moderate 've'-- In Sweden January. 29, 1949 *'tion in heating the 'water which surrounds these .obtained which one'l'aye'r ofriettin'g to then'ext in the direction in the lower and disposed within the combustion chamber, said guide members being so shaped and located that'they catch the incoming air flowing through heregenerator and convey it to the opposite endof the combustion chamber.

In the latter case'th'e breathin'g through the regenerator will be independent of the cooperation' of the thermo circulation, and the breathing aperture may for instance part of the furnace, provided the incoming air flow has a sufficiently high velocity.

In boilers embodying the invention and subject to" widely varying loads'the first mentioned device-is preferred.

Fig. Iis avertical oftheinvention; M

Fig; 2is asectional'vicwtaken'on the lineII-II ofFig'. 1, and

Fig. 3 is a vertical sectionalviewbf'a'm'odifica "tion' of the invention.

Figs. 1 and 2'i11ustrate mentioned device. chamber l, which has thermally conductive walls for the transfer of heat therethrou'gh'for utiliza-'= walls, is entirely closed, exceptiora circular aper turez'in" which a heat exchangingregenerator'3' is'mount'ed. The regenerator is preferably made of finewi'res'in'theform of a plurality of spaced mission between the layers is prevented as much as possible; When breathes through theregenerator a temperature'is' successively falls' in stagesfrom' of the'gasfiowand successively'rises in stages in the direction of'the'ai'r flow.

With such a regenerator it is possibleto'cool the flue gasto a" few-degrees above the tempera ture of the incoming combustion air. An ample surplus of air may be used for thecombustion, Without this causing any considerable losses in exhaust heat,

through ah-adjustable resistance 1.

A'itenthe uaermiaent combustion has beenbe located in the upper sectional view of one farm:

'aboiler with such a first" The cylindrical combustion"- the combustion chamberv ari'd'will provide the'necessary' con- 1 diti'oz'is' for complete combustion. Thus ahigh' pump '4 through a nozzle 5;"

which current is supplied during started, the ignition current may be cut off as the combustion keeps the ignition plug glowing. Only at a very low load on the boiler will the ignition plug have to be supplied with a small amount of current. The control for the glow plug should preferably be connected to the fuel pump control, so that the ignition current is automatically supplied when a small quantity of fuel is injected. There is a possibility of arranging a catalytically operating ignition member, whereby the ignition current may be dispensed with, if the combustion is started with a fuse.

The flue gas which is intermittently discharged the operation of the device is shaped by a round shield 8, on the outside of the regenerator, into an annular jet, which is diverted into an annular collecting chamber 9 from which it is conveyed to the flue or chimney 10. The latter is here entirely relieved of any duty of generating a draught and is only required to deliver the flue gas to the exterior.

During the suction period air is drawn in through an annular slot H and is distributed systematically over the regenerator whilst flowing to the furnace. A symmetric distribution of gas and air through the regenerator is prerequisite for utilizing small differences of temperature without causing condensation of the moisture content of flue gases on the heat transmitting surfaces of the regenerator.

Figure 3 shows an embodiment of a modified form of the invention, in which a regenerator 3a is disposed at the upper end of a vertical cylindrical combustion chamber la. The burnt gases expelled from combustion chamber la pass upwardly through regenerator 3a. and are caught by an upwardly and outwardly flaring chimney 9a, operating as a diffuser which conveys the burnt gases to the flue (not shown).

In this case, the regenerator should be so dimensioned as to cause relatively high velocities of air and burnt gas flow in and out through the regenerator, thus permitting the incoming combustion air to be shaped as a downwardly directed jet capable of penetrating to the bottom of the combustion chamber where there is provided an upturned ignition arch 12. In order to prevent the incoming air jet from mixing immediately with the surrounding burning gases, 2. downwardly and outwardly flaring frusto-conical guide member or diffuser I3 is mounted within the combustion chamber la. with its smaller upper end in proximity to the regenerator 3a. This guide member is preferably formed as a heat'transmit ting surface. As the heat transmitting surface [4 of the boiler as a whole here is suggested to be in the form of pipe coils the guide means l3 should also preferably be in the form of a tightwound pipe coil and may be provided with an inner coating of refractory or other suitable fireproof material.

Fuel is continuously supplied through a control valve I5 to a vertically directed portion of a pipe 15 which passes centrally through the regenerator 3a into the upper end of the combustion chamber la. Pipe 16 is provided at its lower end with a nozzle l1, through which the gas in the furnace is pumped in and out by means of a piston pump [8, which in this case should not have any valves.

In this way there will be no unidirectional flow through the regenerator, which otherwise would be the case, should the fuel be atomized by means of compressed air supplied from the exterior of the furnace. A slight blast action is required by the burner in order to start an inverted combustion of this kind. When the breathing of the furnace has been well started, the circulation is maintained in the desired direction by the intermittently drawn in air which is shaped into a downwardly directed jet diffused by guide member I3. The combustion is started by throwing a burning fuse onto the bottom of the furnace.

This type of combustion device may also be arranged to be fueled with pulverized coal. It may also be constructed for fitting the breathing aperture in its lower end which however, naturally causes changes in the other devices, for instance in accordance with Fig. 1.

Having now particularly described the nature of my invention and the manner of its operation what I claim is:

1. Heating apparatus of the class described, comprising: a combustion chamber having an aperture therein, said combustion chamber being otherwise closed, said combustion chamber comprising thermally conductive walls through which heat may be transferred for utilization; gas permeable heat exchanging means disposed in said aperture for alternate passage therethrough of combustion air and burnt gases; intermittently operating means for injecting fuel into said chamber for periodically producing a combustible mixture therein; means for igniting said combustible mixture; a flue for carrying away the burnt gases; and means for directing burnt gases from said heat exchanging means into saidflue, whereby heat will be transferred from said burnt gases to said heat exchanging means during passage of said burnt gases therethrough, and from said heat exchanging means to air entering said combustion chamber as the burnt gases remaining in the combustion chamber contract by transfer of heat to said thermally conductive walls.

2. Heating apparatus according to claim 1, wherein said gas permeable heat exchanging means comprises a plurality of spaced layers of wire mesh netting.

3. Heating apparatus according to claim 1, wherein said fuel injecting means comprises a nozzle disposed centrally with respect to said heat exchanging means.

4. Heating apparatus according to claim 1, wherein said aperture is disposed in the top of said combustion chamber, and further comprising guide means disposed within said combustion chamber for directing said combustible mixture toward the bottom of said combustion chamber, said guide means comprising a downwardly extending hollow frusto-conical guide member ineluding a heat transfer surface, said guide mem her being disposed with the smaller end of said frusto-conical configuration located in proximity to said heat exchanging means.

5. Heating apparatus according to claim 1, wherein said aperture is disposed in the bottom of said chamber, and wherein said burnt gas directing means comprises a round shield disposed beneath said aperture for shaping the burnt gases into an annular jet and an annular collecting chamber is connected to said flue and encircles said round shield and is spaced therefrom to provide an annular opening for the admission of air to said heat exchange means.

6. Heating apparatus according to claim 1, in which said igniting means comprises:' a glow plug; an electrical circuit for energizing said glow plug; and adjusting means in said 'electrical circuit for controlling the energization of said glow plug, whereby said igniting means may be controlled for ignition of said combustible mixture at times when the thermal load supplied by said heating apparatus is reduced.

7. Heating apparatus according to claim 1, wherein said intermittently operating fuel injecting means comprises: a valveless reciprocating plunger pump; a pipe connecting said pump to said combustion chamber; and a controllable fuel supply line communicating with said pipe.

8. Heating apparatus according to claim 7, wherein said heat exchanging means is disposed at the top of said combustion chamber, said pipe passes centrally through said heat exchanging means into said combustion chamber, and in which said pipe terminates in a downwardly directed nozzle.

9. Heating apparatus according to claim 1, wherein said aperture is disposed in the top of said combustion chamber, and in which said thermally conducting walls include the walls of pipes carrying fluid to be heated, further comprising a downwardly extending hollow frustoconical guide member disposed within said com- ERIK TORVALD LINDEROTH.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,102,345 Lemale July 7, 1914 1,217,698 Brown Feb. 27, 1917 1,474,867 Walker Nov. 20, 1923 1,811,654 Shepherd June 23, 1931 1,923,614 Clarkson Aug. 22, 1933 1,993,748 Noack Mar. 12, 1935 2,525,782 Dunbar Oct. 17, 1950 2,563,028 Goddard Aug. 7, 1951 2,574,460 Bohanon Nov. 13, 1951 

